Screw-jack



(No Model.) 2 Sheets--Sheet 1.

A. R. TIFFANY.

SCREW J-AGK.

No. 295,888. r Patented Man 25, 1884.

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(No Model.) 2 Shets-Sheet 2.

. A. R. TIFFANY.

SGREW JACK.

No. 295,838. Patented'Mar. 25, 1884.

In pen? minnow UNTTEE STATES PATENT OEFIcE.

ALBERT R. TIFFANY, OF DAYTON, OHIO, ASSIGNOR OF FIVE-SIXTHS TO MICHAEL NEIL, HORACE L. GILLETTE, AND JOHN J. LELAND, ALL OF SAME PLACE.

SCREW-JACK.

' SPECIPICATIQN forming part of Letters Patent No. 295,838, dated March 25, 1884:.

. Application filed January 26, 1884. i (No model.)

To aZZ ZUhOflQ/ifi' may concern; Be it known that I, ALBERT B. TIFFANY, of Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in-Screw-Jacks; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the V figures and letters of reference marked thereon.

My improvement will be first described in connection with the accompanying drawings, and will then be pointed out particularly in the claims at the end of this specification.

In said drawings, Figure 1 represents a side elevation of a screwjack constructed in accordance with my invention; Fig. 2, a longitudinal vertical section of the same; Fig. 3, a

horizontal section taken on the line x m, Fig.

1. Fig. 4 is a view showing the hub carrying the worm-wheel and ratchet. Fig. 5 is a perspective View of the two-part nut in which the main screw-shaft works.

Similar letters of reference in the several figures indicate the same parts.

The letter A designates the standard of the jack, in or upon which the various working parts are mounted.

B is the main screw-shaft, carrying at its upper end a rotatablehead, O, constructed and applied in any suitable manner.

D isa screw-nut divided centrally and vertically into two parts, and having vertical side walls and inclined end walls, d cl,whieh work againstthe correspondingly-shaped inner faces of the standard A, as shown in Fig. 2. I term this nut a gravitating nut, from the fact that its parts, from their weight and the inclination of theirends, automatically drop down and crowd together and into engagement with the main screw-shaft. Each of the parts of the gravitating nut is provided with an inclined groove, 0, into which projects a corresponding inclined rib, f, formed upon the wall 4 5 of the standard, from which it results that when the 'nut is raised its parts are caused to separate and assume the position shown in dotted lines, Fig. 2. A loose key, 9, is inserted in corresponding horizontal grooves in the sides of both the nut-sections, for the purpose of keeping the parts of the nut always in the same horizontal plane and preventing them from rising or fallingunequally. The norinal position of the nut is preserved by the mereweight of its parts; but to raise it I pro vide a footlever, H, pivoted at the base of the standard and connected by separate rods, h h, to the respective sections. When the footlever is depressed, the nut-sections are raised and caused to spread apart by reason of their. fixed and positively-acting inclined guides until finally they are entirely released from engagement with the screw-shaft, in which position they allow said shaft to drop down to its lowest position.

The means employed for raising the screwshaft consist, briefly, of a hub, I, having at its lower end a worm-wheel, J, with 'which meshes a worm, J, on a shaft, J", and having at its upper end a ratchet, K, with which cooperates a pawl, Z, carried by'avibrating handle, L. This huh I has a smooth bore and fits upon the screw-shaft B, and is provided with a'feather or tongue, t, which enters a longitudinal groove, b, in the shaft, and which, while it permits the shaft to be freely adjusted up and down without disturbing the hub, causes any rotary movement of the hub to be imparted to the shaft, so as to raise or lower it. The end of the shaft J is provided with a ratchet-wheel, M, with which engages a pawl, N, carried by a vibrating arm, 0 The shaft J is preferably mounted in adjustable bearings P P, which permit it to be adjusted in and out, so as to cause its worm J toengage with or disengage from the worm-wheel J at pleasure. The pawls Z and N and their respective ratchets are preferably arranged so as to be worked either. to the right or to the left, as will be readily-understood. When it is desired to move with the jack a moderate weight only,the worm J is adjusted back out of engagement, and the hubIis rotated by the action of the hand-lever L, pawl Z, and ratchet 7a, and by its rotation causes the screw-shaft to be turned in the gravitating nut and to be raised or lowered with a-comparatively rapid motion, according to the direction of rotation; but when a very heavy weight is to be moved, requiring the application of greater power, and Ioo tion without the intervention of the moreslowly acting rotary hub. For instance, by pressing the foot on the treadle when the shaft is at its lowest pointof adjustment, the gravitatin'g nut can be freed from the shaft B, and the latter be drawn instantly to a higher elevation and there maintained by simply rcleasing the treadle and allowing the gravitating nut to fall; or if it is desired to lower the screw from ahigher clevation,it can be automatically accomplishedby pressing on the treadle till the nut is relieved of the shaft,when the latter will drop automatically of its own weight.

It Will be observed that the standard or casing of my jack is so constructed as to entirely inclose the operative parts of the device and prevent access to the same of water, snow, ice, sand, dirt, or anything else which would tend to injure or clog them and impair their action. This feature I deem of much practical importance.

I claim as my invention- 1. In a screw-jack, the combination of a screwshaft and a divided gravitating nut having inclined ends with a standard or case having inclined bearing-faces for the ends of the nut to work against, substantially as described.

2. In a screw-jack, the combination of a screw-shaft, a divided gravitating nut having inclined ends, and fixed and positively-acting guides for opening and closing the parts of the nut, with a standard or case having inclined bearing-faces for the ends of the gravitating nut to work against, substantially as described.

3. In a screw-jack, the combination, with the screw-shaft, of a divided gravitating nut, guides for positively opening and closing it, and means for keeping its parts in the same 6. In a screw-jack, the combination, Withthe screw-shaft, of the divided nut whose parts gravitate toward the screw-shaft, operatingtreadle pivoted to the base of the jack, and connections for raising the nut by the operation of the treadle, substantially as described.

-7. In a screw-jack, the combination, with the screw-shaft, of the elongated hub having the feather projecting into the groove in the shaft, and having also the worm-gear and the ratchet at opposite ends for the application of the worm and the pawl-arm, respectively, substantially as described.

8. In a screw-jack, the combination, with the screw-shaft, of the divided gravitating nut and its guides, the elongated hub acting upon the shaft, and means for rotating said hub, substantially as described.

9. In a screw-jack, the combination, with the screwshaft, of the divided gravitating nut and its guides, the elongated hub having the wormgear, with the worm for engaging with the worm-gear, and the means for adjusting the said worm into or out of engagement, substantially as described.

10. In a screw-jack, the combination, with the screw-shaft, of the divided gravitating nut and its guides, the elongated hub having the upper ratchet and the lower worm-gear, the upper lever and its pawl, and the adjustable worm and means for operating it, substantially as described.

FRED F. CHURCH, MIcHL. NEIL. 

